As computational demands increase, there is a growing need for a large number, i.e., greater than 600, of electrical signal connections for removable printed circuit boards. Typically, removable printed circuit boards are inserted into a card cage or expansion slot of a computer. Often, these printed circuit boards, or daughter cards, are connected to the mother board of a computer through the backplane of the card cage. Electrical circuitry on the circuit boards connect to the backplane by any of several types of known connectors and terminals. The circuit boards are thereby interconnected by the backplane to circuitry of other circuit boards in the array of slots and/or to other circuitry within the computer. The circuit boards are, therefore, limited by the number of electrical connections available on the backplane.
For example, printed circuit boards of the Eurocard 9 U by 400 mm format have three 96 pin DIN connectors along their back edge. Most of these connections are dedicated to VME signal lines and power supplies. Thus, at most, approximately 100 connections are available for non-standard power supplies and signal connections. The complexity of today's electronics demand more connections to exchange power and electrical signals.
One solution is to add connections to the front of the circuit board. Adding connections to the front edge of the circuit board is possible, however, it is not practical for large systems. The associated cabling would make circuit board removal and replacement very difficult.
The present printed circuit board card connection system addresses this need for increased signal connections with a simple mechanical arrangement.
It is therefore an object of the present invention to provide a card connection system having 1000 or more electrical signal connections disposed along an edge of a printed circuit board, other than the back edge.
Another object of the present invention is to provide electrical connections which are able to be mated after insertion, yet separable during circuit board insertion and extraction.
A further object of the present invention is to provide a card connection system which provides adequate ventilation when a plurality of circuit boards including the present connection system are installed as an array within a card cage.